I have Parallels Build 3120 installed on a Macbook Pro 17" w/2GB RAM. The guest virtual machine is Red Hat Advanced Server 4.0. The native resolution of the LCD on the 17" Pro is 1680x1050. I have added this custom resolution to Parallels and set up the /etc/X11/xorg.conf file. When I run "startx", the Xserver starts fine and I get scrollbars on the edges of the screen, as expected, for the small area that's offscreen due to the Finder title bar. However, whenever I try to switch to fullscreen, I get the following message: Unable to switch to Full Screen Mode. Primary operating system does not support screen resolution requested by guest operating system. Select another resolution for the guest operating system or review your video system configuration. I've tried various color depths and modelines to no avail. Is 1680x1050 even possible on the MBP?
